skeleton.c

伯克利的语法分析器的创建工具

#include "defs.h"

/*  The three line banner used here should be replaced with a one line	*/
/*  #ident directive if the target C compiler supports #ident		*/
/*  directives.								*/
/*									*/
/*  If the skeleton is changed, the banner should be changed so that	*/
/*  the altered version can easily be distinguished from the original.	*/

char *banner[] =
{
    "#ifndef lint",
    "char yysccsid[] = \"@(#)yaccpar	1.4 (Berkeley) 02/25/90\";",
    "#endif",
    0
};


char *header[] =
{
    "#define yyclearin (yychar=(-1))",
    "#define yyerrok (yyerrflag=0)",
    "#ifndef YYSTACKSIZE",
    "#ifdef YYMAXDEPTH",
    "#define YYSTACKSIZE YYMAXDEPTH",
    "#else",
    "#define YYSTACKSIZE 300",
    "#endif",
    "#endif",
    "int yydebug;",
    "int yynerrs;",
    "int yyerrflag;",
    "int yychar;",
    "short *yyssp;",
    "YYSTYPE *yyvsp;",
    "YYSTYPE yyval;",
    "YYSTYPE yylval;",
    "#define yystacksize YYSTACKSIZE",
    "short yyss[YYSTACKSIZE];",
    "YYSTYPE yyvs[YYSTACKSIZE];",
    0
};


char *body[] =
{
    "#define YYABORT goto yyabort",
    "#define YYACCEPT goto yyaccept",
    "#define YYERROR goto yyerrlab",
    "int",
    "yyparse()",
    "{",
    "    register int yym, yyn, yystate;",
    "#if YYDEBUG",
    "    register char *yys;",
    "    extern char *getenv();",
    "",
    "    if (yys = getenv(\"YYDEBUG\"))",
    "    {",
    "        yyn = *yys;",
    "        if (yyn >= '0' && yyn <= '9')",
    "            yydebug = yyn - '0';",
    "    }",
    "#endif",
    "",
    "    yynerrs = 0;",
    "    yyerrflag = 0;",
    "    yychar = (-1);",
    "",
    "    yyssp = yyss;",
    "    yyvsp = yyvs;",
    "    *yyssp = yystate = 0;",
    "",
    "yyloop:",
    "    if (yyn = yydefred[yystate]) goto yyreduce;",
    "    if (yychar < 0)",
    "    {",
    "        if ((yychar = yylex()) < 0) yychar = 0;",
    "#if YYDEBUG",
    "        if (yydebug)",
    "        {",
    "            yys = 0;",
    "            if (yychar <= YYMAXTOKEN) yys = yyname[yychar];",
    "            if (!yys) yys = \"illegal-symbol\";",
    "            printf(\"yydebug: state %d, reading %d (%s)\\n\", yystate,",
    "                    yychar, yys);",
    "        }",
    "#endif",
    "    }",
    "    if ((yyn = yysindex[yystate]) && (yyn += yychar) >= 0 &&",
    "            yyn <= YYTABLESIZE && yycheck[yyn] == yychar)",
    "    {",
    "#if YYDEBUG",
    "        if (yydebug)",
    "            printf(\"yydebug: state %d, shifting to state %d\\n\",",
    "                    yystate, yytable[yyn]);",
    "#endif",
    "        if (yyssp >= yyss + yystacksize - 1)",
    "        {",
    "            goto yyoverflow;",
    "        }",
    "        *++yyssp = yystate = yytable[yyn];",
    "        *++yyvsp = yylval;",
    "        yychar = (-1);",
    "        if (yyerrflag > 0)  --yyerrflag;",
    "        goto yyloop;",
    "    }",
    "    if ((yyn = yyrindex[yystate]) && (yyn += yychar) >= 0 &&",
    "            yyn <= YYTABLESIZE && yycheck[yyn] == yychar)",
    "    {",
    "        yyn = yytable[yyn];",
    "        goto yyreduce;",
    "    }",
    "    if (yyerrflag) goto yyinrecovery;",
    "#ifdef lint",
    "    goto yynewerror;",
    "#endif",
    "yynewerror:",
    "    yyerror(\"syntax error\");",
    "#ifdef lint",
    "    goto yyerrlab;",
    "#endif",
    "yyerrlab:",
    "    ++yynerrs;",
    "yyinrecovery:",
    "    if (yyerrflag < 3)",
    "    {",
    "        yyerrflag = 3;",
    "        for (;;)",
    "        {",
    "            if ((yyn = yysindex[*yyssp]) && (yyn += YYERRCODE) >= 0 &&",
    "                    yyn <= YYTABLESIZE && yycheck[yyn] == YYERRCODE)",
    "            {",
    "#if YYDEBUG",
    "                if (yydebug)",
    "                    printf(\"yydebug: state %d, error recovery shifting\\",
    " to state %d\\n\", *yyssp, yytable[yyn]);",
    "#endif",
    "                if (yyssp >= yyss + yystacksize - 1)",
    "                {",
    "                    goto yyoverflow;",
    "                }",
    "                *++yyssp = yystate = yytable[yyn];",
    "                *++yyvsp = yylval;",
    "                goto yyloop;",
    "            }",
    "            else",
    "            {",
    "#if YYDEBUG",
    "                if (yydebug)",
    "                    printf(\"yydebug: error recovery discarding state %d\
\\n\",",
    "                            *yyssp);",
    "#endif",
    "                if (yyssp <= yyss) goto yyabort;",
    "                --yyssp;",
    "                --yyvsp;",
    "            }",
    "        }",
    "    }",
    "    else",
    "    {",
    "        if (yychar == 0) goto yyabort;",
    "#if YYDEBUG",
    "        if (yydebug)",
    "        {",
    "            yys = 0;",
    "            if (yychar <= YYMAXTOKEN) yys = yyname[yychar];",
    "            if (!yys) yys = \"illegal-symbol\";",
    "            printf(\"yydebug: state %d, error recovery discards token %d\
 (%s)\\n\",",
    "                    yystate, yychar, yys);",
    "        }",
    "#endif",
    "        yychar = (-1);",
    "        goto yyloop;",
    "    }",
    "yyreduce:",
    "#if YYDEBUG",
    "    if (yydebug)",
    "        printf(\"yydebug: state %d, reducing by rule %d (%s)\\n\",",
    "                yystate, yyn, yyrule[yyn]);",
    "#endif",
    "    yym = yylen[yyn];",
    "    yyval = yyvsp[1-yym];",
    "    switch (yyn)",
    "    {",
    0
};


char *trailer[] =
{
    "    }",
    "    yyssp -= yym;",
    "    yystate = *yyssp;",
    "    yyvsp -= yym;",
    "    yym = yylhs[yyn];",
    "    if (yystate == 0 && yym == 0)",
    "    {",
    "#ifdef YYDEBUG",
    "        if (yydebug)",
    "            printf(\"yydebug: after reduction, shifting from state 0 to\\",
    " state %d\\n\", YYFINAL);",
    "#endif",
    "        yystate = YYFINAL;",
    "        *++yyssp = YYFINAL;",
    "        *++yyvsp = yyval;",
    "        if (yychar < 0)",
    "        {",
    "            if ((yychar = yylex()) < 0) yychar = 0;",
    "#if YYDEBUG",
    "            if (yydebug)",
    "            {",
    "                yys = 0;",
    "                if (yychar <= YYMAXTOKEN) yys = yyname[yychar];",
    "                if (!yys) yys = \"illegal-symbol\";",
    "                printf(\"yydebug: state %d, reading %d (%s)\\n\",",
    "                        YYFINAL, yychar, yys);",
    "            }",
    "#endif",
    "        }",
    "        if (yychar == 0) goto yyaccept;",
    "        goto yyloop;",
    "    }",
    "    if ((yyn = yygindex[yym]) && (yyn += yystate) >= 0 &&",
    "            yyn <= YYTABLESIZE && yycheck[yyn] == yystate)",
    "        yystate = yytable[yyn];",
    "    else",
    "        yystate = yydgoto[yym];",
    "#ifdef YYDEBUG",
    "    if (yydebug)",
    "        printf(\"yydebug: after reduction, shifting from state %d \\",
    "to state %d\\n\", *yyssp, yystate);",
    "#endif",
    "    if (yyssp >= yyss + yystacksize - 1)",
    "    {",
    "        goto yyoverflow;",
    "    }",
    "    *++yyssp = yystate;",
    "    *++yyvsp = yyval;",
    "    goto yyloop;",
    "yyoverflow:",
    "    yyerror(\"yacc stack overflow\");",
    "yyabort:",
    "    return (1);",
    "yyaccept:",
    "    return (0);",
    "}",
    0
};


write_section(section)
char *section[];
{
    register int i;

    for (i = 0; section[i]; ++i)
    {
	++outline;
	fprintf(output_file, "%s\n", section[i]);
    }
}